Overview
A delusion refers to a false belief that is so sincerely held that it seems impossible to change through logic, reason, or an appeal to values.
The third and fourth editions of theDiagnostic and Statistical Manual of Mental Disorders defined delusions as “false beliefs due to incorrect inference about external reality.” The DSM-V defines them as “fixed beliefs that are not amenable to change in light of conflicting evidence.” Many clinicians and researchers have criticized these definitions:
“These definitions are by no means ‘operational’ in any scientific sense of the term and are in many respects also empirically incorrect (1,5). Most importantly, they all deal with what have been consistently considered as ‘delusion-like ideas’, ‘secondary’ or ‘second-rank’ delusions, which reflect variously determined judgmental errors. However, it is the ‘true’, ‘primary’ or ‘ontological’ delusion (1) that constitutes the central concern of psychopathology, because it holds a key to grasping the mental life in schizophrenia, with pathogenetic and diagnostic implications (5).” 1